In space and in nations around
the world, preparations for the next steps in the orbital assembly
of the International Space Station are entering the home stretch this
week.

As the Space Shuttle Discovery
is readied for a May 20 launch on the next Station assembly mission,
flight controllers in Russia and the United States will conduct a
"dress rehearsal" of the Shuttle's upcoming docking with
the international orbiting laboratory. Simultaneously, the next major
station component, the Russian-provided early living quarters, is
scheduled to depart the Moscow factory where it was built and be shipped
by train to the Russian launch site at the Baikonur Cosmodrome in
Kazakstan. Planned for launch on a Russian rocket this fall, the living
quarters, previously known by the technical term Service Module, was
recently named Zvezda, which translates to "Star" in English.

On Wednesday, flight controllers
plan to maneuver the Station to the same orientation it will be in
for the docking of Discovery. The docking rehearsal will maneuver
the Station from its present orientation, a slow spin with the Unity
module pointing to Earth and Zarya toward space, to an orientation
that is horizontal to Earth's surface, with Zarya pointed in the Station's
direction of travel. The Station will remain in the horizontal orientation
for about three hours while the Zarya module's guidance system is
calibrated using the horizon of Earth as a point of reference. Then,
the Station will maneuver to an orientation again perpendicular to
Earth's surface, but without any spin and with Unity pointing to space
and Zarya to Earth - the same orientation required for Discovery's
docking.

The Station will remain in
the docking orientation for about four and half hours - three orbits
of Earth - completing its test and then return to its original, spinning
attitude. The spinning attitude, with Unity to Earth and Zarya to
space, is the preferred orientation for the station's day-to-day uncrewed
operations to optimize sunlight on the electricity-generating solar
arrays and to provide moderate heating and cooling on the spacecraft.

Flight controllers are continuing
to troubleshoot a problem with a portion of the Unity module's communication
system, and they are finalizing plans for Discovery's crew to repair
the system. Called the Early Communications System, Unity's communications
system is a backup to the primary station communications system located
in the Zarya module and continues to operate well. The problem with
the Unity system has not hampered operations of the Station and poses
no problems for the docking with Discovery.

Late last week, flight controllers
noted a false indication from one of the eight smoke detectors operating
within Zarya. The faulty detector was powered off, and sufficient
smoke detection remains available onboard while the problem is being
analyzed.

In less than two weeks, flight
controllers will begin powering up heaters onboard the Station to
begin warming it in anticipation of the arrival of Discovery. This
Shuttle flight will bring almost two tons of supplies, preparing the
new outpost for the arrival of the Zvezda module this fall and laying
out a welcome mat for the first resident Station crew that is planned
to launch early next year. Updates on the status of Discovery's launch
preparations are available on the Internet at:

The International Space Station
is in an orbit with a high point of 252 statute miles and a low point
of 238 statute miles, circling the Earth once approximately every
92 minutes. The Station has completed more than 2,600 orbits of Earth
since its launch. As it passes overhead at dawn or dusk, the 35-ton
complex is easily visible from the ground, and it will become even
brighter once Discovery has docked. Space Station viewing opportunities
for locations worldwide are available on the Internet at: